From September 2006 to a August 2007, a proof of concept test of ET-DSP ™ (Electro-Thermal Dynamic Stripping Process) was completed by E-T Energy Ltd. A numerical simulation study was done prior to the field test to quantify performance metrics, such as the amount of water usage per m3 of produced oil, the energy input requirements, kW-hr/m3 of oil (i.e. an equivalent Steam Oil Ratio value), green house gas emissions, drilling performance, operating costs, and process facility design.
Field performance met or exceeded expectations. The recovery factor was greater than 75%, the energy requirement per m3 of oil produced was 23% less than calculated and peak production rates were greater than expected. The water oil ratio was one with no green house gas emissions in heating the oil. An insignificant volume of sand was produced and the oil recovered had very little to no emulsions.
A comparison of the data with theory reveals that not all the drive mechanisms were considered in the initial numerical simulation. One of the more significant is the contribution of associated gas. Albeit in relatively small amounts, the gas evolving from the bitumen with rising temperature displaced the bitumen from the pore volume and accelerated recovery from the production wells.
Electrical-thermal heating of the Alberta oil sands has been studied since the early 1970's [1],[2],[7],[6],[8],[4]. Heat is created in the bitumen reservoir as electrical current passes through the connate water as depicted in Figure 1. At low frequency, the reservoir behaves like a resistor, and the conversion of electrical energy to heat is by ohmic losses.
This paper compares data from a pilot test of the Electro- Thermal Dynamic Stripping Process, ET-DSP ™ process [4] with numerical simulation (details are published in reference [5]. Construction and operations of the test was carried out from September 2006 to August 2007.
The objectives of the proof of concept are to:
Determine the percent Recovery Factor, Ro,
Establish the Energy Oil Ratio (EOR), i.e., the kWh/bbl of produced bitumen.
Determine the water consumption on a per barrel of produced bitumen, Water Oil Ratio m3/m3, (WOR),
Confirm numerical simulation temperature predictions, And
Develop equipment and facility design basis, well completions, operating procedures, and economic parameters for commercial development.
Table 1 summarizes the comparison between numerical model predictions and results from the pilot test. The recovery factor achieved in the proof of concept was within the model prediction. The energy consumption was less than the model predicted by 23%. Converting the energy in terms of an equivalent Steam Oil Ratio, SORe = 0.49, or a Net Energy Ratio (NER) of 30 times more energy produced in the bitumen than used to produce it. The ratio of water used per produced barrel of bitumen was predicted to be one; slightly less than one was achieved in the proof of concept.
A comparison of the modeled and actual temperature response at observation well (OB05) is shown in Figure 2. OB05 is located approximately mid way between the electrode wells.
